The invention described herein arose in the course of, or under, Contract No. DE-AC08-83NV10282 between the U. S. Dept. of Energy and EG&G Energy Measurements, Incorporated.
Optical fibers such as silica glass fibers are normally constructed with a cladding material such as a plastic or glass cladding which is capable of reflecting the light as it is being transmitted through the optical fiber. The clad fiber is then provided with a jacket or buffer material which protects this cladding material when a number of such fibers are bundled together to form a cable.
It is necessary, however, to remove this outer buffer or jacket when it is desired to splice fibers together or to terminate the fiber in a device such as connector, an array body which holds the fibers in proper alignment, etc.
Conventionally, wire strippers which are used to remove insulation from a metal wire, have been used to remove such jacketing or buffer material from optical fibers. Such wire strippers have been produced with various sized openings which generally match the diameter of the wire from which the outer insulation is being removed to avoid mechanical damage such as cutting or scoring of the metal wire which would tend to mechanically weaken the wire resulting in possible breakage of the wire at that point.
An example of such a cutter is found in Perrino et al U.S. Pat. No. 4,271,729, cross-reference to which is hereby made. The cutter described therein is provided with cutting blades having complimentary semicircular notches therein sized, with respect to the diameter of the wire to be stripped, to permit penetration of the insulation without nicking the wire itself.
However, while such wire stripping devices do provide sufficient protection against damage to a metal wire by providing a notch in the cutting blade slightly larger than the diameter of the wire, the use of such a device in removal of the jacket or buffer layer of an optical fiber does not prevent damage to the cladding material on an optical fiber. This is because such wire strippers rely on the relative difference in the hardness of the inner wire versus the insulation to properly center the cutting surfaces of the stripping blades. In other words, provided that the notch or opening in the blades is slightly larger in diameter than the wire, if one of the blades cuts through the insulation and engages the wire before the other blade has severed the insulation, the engaged blade will act to center the wire by urging the wire and insulation thereon toward the blade which has not yet cut through the insulation.
While such wire stripping designs have been successful in preventing scoring damage to a metal wire, they have not prevented damage from occurring to the cladding of optical fibers when such stripping devices are used to remove the outer jacket or buffer material therefrom. This is because damage to the metal wire will not occur unless the blade actually indents the surface of the metal wire, while damage to an optical fiber can occur due to mere scratching of the cladding layer thereon.
Thus, removal of an outer protective jacket or buffer layer from an optical fiber requires not only correct diameter sizing of notched blades of a stripping device with the diameter of the optical fiber, but also precise axial alignment of the cutting blades of the stripper device with the axis of the optical fiber as well.